Seismic retrofit of plain concrete piers of railroad bridges using composite of FRP-steel plates

This study is planed to solve the overturning problem and manifestation of tensile cracking of plain concrete piers of railroad bridges. For the overturning problem, earth anchors are used to fix the bottom of a pier to a rock-foundation using prestressing cables. Composite of Fiber Reinforced Polymer (FRP) and steel plates (FSP) are attached longitudinally on the surface of the pier to prevent cracking. Then, FRP band strips are wrapped onto the composite of FRP and steel plate to provide lateral confinement. Push-over tests in field show that the earth anchors are effective in preventing the overturning of the pier, and that the FSPs and the FRP strips prevent the cracking of concrete and increase the strength in bending.